Nucleolar organizing regions in primary intracranial malignant lymphomas

Twenty-two non-immunocompromised patients with primary intracranial malignant lymphomas were examined on surgical material by using an argyrophilic method for the demonstration of nucleolar organizer regions as Ag-NORs. The histopathological classifications of 22 patients included 3 small lymphocytic, 7 small cleaved, 9 large cell. 1 mixed large and small, and 2 small non-cleaved type. The numbers of Ag-NOR of malignant lymphoma patients varied from 1.36 to 5.02 (mean 3.46 +/- 0.25). The mean Ag-NOR numbers in the histopathological subtypes were small lymphocytic 1.63, small cleaved 3.18, large 4.21, mixed large and small 3.47, and small non-cleaved 3.78. The number of Ag-NORs in small lymphocytic type was significantly less than small cleaved or large cell type (p < 0.05). The small cleaved type also had a smaller Ag-NOR number than the large cell type (p < 0.05). Except for two patients who had postoperative deterioration, 20 patients received postoperative irradiation ranging from 36 to 54 Gy (median, 46 Gy). Sixteen patients had complete response to radiotherapy, and 4 had good partial response. Ten patients had tumor recurrence within the remission period of 3 months to 7 years and 10 months (median 4.8 months). Three patients with intracranial relapse at a remote site had a significantly longer remission period (mean 57.3 months) than 7 with local relapse (mean 6.29 months), p < 0.05. The mean Ag-NOR number of the short and long remission period were 3.13 +/- 0.34 and 3.8 +/- 0.80, respectively. No significant difference was found between these two groups. The survival period was 3.2 months to 12 years (median 20 months). The Ag-NOR numbers of survival period less than or more than 20 months were 3.62 +/- 0.40 and 3.27 +/- 0.37, respectively. The Ag-NOR numbers did not correlate with either the remission or the survival period. These results indicate that Ag-NOR numbers may correlate with the histopathologic types, but not with the prognosis of primary intracranial malignant lymphomas.